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Objective To investigate the effects of long-term low-dose radiation (LDR) of γ-rays on the proliferation and radiosensitivity of human lymphoblast cells HMy2.CIR (HMy) and to elucidate the underlying mechanism.Methods HMy cells were divided into control group and long-term LDR group.For the long-term LDR treatment,HMy cells were fractionally exposed to a low dose of γ-rays,which could enhance cell proliferation,3 times per week for 4 weeks.After the long-term LDR exposure,part of the control and long-term LDR exposed cells were further irradiated with a challenging dose (2 Gy) of γ-rays.Then cell proliferation and radiosensitivity were assayed by CCK-8 kit,cell apoptosis,and γ-H2AX formation was measured by flow cytometry.Gene expressions of cyclinD1,PCNA,bcl-2 and bax were detected by RT-PCR.Results The long-term LDR significantly increased cell proliferation (t =9.607,P ＜ 0.01) accompanied with up-regulation of cell cycle regulation gene cyclinD1 (t =6.869,P ＜ 0.01),proliferation regulation gene PCNA (proliferating cell nuclear antigen) (t =9.229,P ＜ 0.01) and bcl-2 gene (t =2.662,P ＜ 0.05),but decreased the expression of pro-apoptotic gene bax (t =19.908,P ＜0.01) in HMy cells.Compared to untreated cells,the long-term LDR decreased cell radiosensitivity (t =8.896,P ＜ 0.01),including apoptosis induction (t =4.762,P ＜ 0.01) and γ-H2AX formation (t =10.264,P＜0.01).Conclusions The long-term LDR promoted cell proliferation by up-regulating cell cycle related genes,while it reduced the radiosensitivity of HMy cells with acquisition of apoptotic resistance.
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Objective To investigate the dose-response of micronuclei (MN) frequency in the lymphocytes irradiated with or without combination of α-particles and γ-rays. Methods Human lymphoblast cells HMy2.CIR were irradiated with 0 - 1 Gy of α-particles,0 - 5 Gy of γ-rays,and 0.025 -0.5 Gy of α-particles followed by different doses of γ-rays,respectively.The micronuclei (MN) in the irradiated cells were measured with the cytokinesis block technique,and the dose-responses of MN were established under different irradiation conditions.Results For γ-ray irradiation,the dose-response of MN was well-fit by the linear-quadratic model with an equation Y =c + αD + βD2.For α-particle irradiation,the MN induction increased linearly with the dose less than 0.250 Gy. But when the dose of α-particles increased continually,the dose-response curve bended and could be well fit with the BaD model Y =c + αD + σ[ 1 - exp( - δD) ] exp( - βD) where radiation-induced bystander effect (RIBE) was indicated.For the combined exposure,the dose-response of MN was similar to that of γ-irradiation when the dose of α-particles was lower than 0.1 Gy,but it was similar to that of α-irradiation when the dose of α-particles was higher.When the dose of α-particles was 0.2 and 0.5 Gy,MN induced by the mixed radiation were significantly higher than the sum of corresponding irradiation alone ( t =5.22 - 11.86,P ＜ 0.05 ).Conclusions The radiation damage of α-particles differs from that of γ-rays,where RIBE may be involved.The combination irradiation of α-particles and γ-rays has a synergistic effect on radiation damage of lymphoblast cells.
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Objective To observe continuous venous-venous hemofiltration (CVVH) for treatments and cares of severe acute pancreatitis(SAP). Methods From August 2004 to August 2006, 15 cases with SAP were in conventional treatment (the control group), from September 2006 to August 2010, 20 cases with SAP were nursed with CVVH(the observation group). We surveyed patients' vital signs (including body temperature, heart rate, breathing and blood pressure),mental symptoms, abdominal signs and monitored liver and kidney functions. Additionally we executed APACHE Ⅱ scores. We analyzed them retrospectively. Results The afore - mentioned indexes of two groups were significant in statistics, the observation group had lower incidence of MODS、MOF than the control group after 10 days caring. Conclusions The CVVH could correct systemic inflammatory reaction of SAP and prevent complications. Standard technical operation and intensive nursing can ensure smooth process of CVVH and decrease complications caused by CVVH.
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Objective To know the effects of partial closure combined with MgSO_4 hydropathic com-press for injury because of highly irritating drugs extravasation. Methods Divided 144 patients with injury because of highly irritating drugs extravasation into the treatment group and the control group randomly, there were 72 cases in each group. 50% MgSO_4 was used in the control gnmp, partial closure was used in the treat-ment group in addition. Compared the medical effects between the two groups. Results Compared with the control group, the medical effects of injury because of highly irritating drugs extravasation in the treat-ment group was better. Conclusions Partial closure combined with MgSO_4 hydropathic compress is a kind of effective method for patients with injury because of highly irritating drugs extravasation, which can quickly promote absort by surrounding tissue and release pains.